粘土固化注浆帷幕对重金属离子的吸附特性

Adsorption of Heavy Metals on Clay-Solidified Grouting Curtain

采用醋酸铵反复作用法测得了不同配比粘土固化浆液结石体的阳离子交换容量,利用原子吸收分光光度仪测定溶液浓度,通过室内吸附平衡实验研究了粘土固化注浆帷幕对重金属离子的吸附特性.结果表明:粘土固化注浆帷幕对Pb2+和Cd2+的吸附能力与浆液配比密切相关,在室温和pH 5.0条件下浆液组分中水泥与粘土质量比为2∶4时吸附能力最强;实验条件下Pb2+的吸附量大于Cd2+;Pb2+和Cd2+之间存在竞争吸附,Pb2+的竞争吸附系数大于Cd2+,且Pb2+的吸附速率大于Cd2+;粘土固化注浆帷幕对Pb2+和Cd2+的吸附过程符合Freundlich等温吸附曲线模型,相关系数在99%以上.

The adsorption of heavy metals on day-solidified grouting curtain was investigated by equilibrium experimentations based on ammonium acetate to determine the cation exchange capacity （CEC）, and on the atomic absorption speetrophotometry to measure the solution concentration. The results showed that the adsorption capacity of heavy metals was closely related to the composition of day-solidified grouting curtain. At room temperature and pH 5 with the cement-clay ratio of 2：4, the adsorption capacity of the day-solidified grouting curtain was the strongest,and the adsorption capacity of Pb^2＋. was muchlarger than that of Cd^2＋ . The adsorption velocity of Pb^2＋. was greater than that of Cd^2＋. when they were competitively adsorbing in the same solution system, and their adsorption process agreed with Freundlieh isotherms model with a correlation coefficient of over 99 %.